The so-called air motors have hitherto been provided as intermittent rotation drive apparatus which utilize air as the power source and employ a pawl-fed intermittent movement mechanism.
In general, such an intermittent rotation drive apparatus has a pawl member capable of moving linearly in response to air pressure so as to cause intermittent rotation of a gear-like rotary body.
An example of such intermittent rotation drive apparatus is known from Japanese Utility Model Publication No. 46241/1983 which discloses a stepping motor.
However, any of the conventionally provided intermittent rotation drive apparatus, such as that described above, is capable of causing, by the use of air pressure, intermittent rotation only in one direction. No apparatus has hitherto been provided that is capable of causing intermittent rotation in either of two directions.
In view of the foregoing, an object of the present invention is to provide an intermittent rotation drive apparatus utilizing air pressure which is provided with means for selecting the direction of rotation, and which thus is thus capable of allowing the direction of rotation to be freely selected.